A fieldbus applied to sensor-actuator monitoring network.

This paper describes a fieldbus of which the physical layer using CAN (Controller Area Network) transmission line and the data link layer using SPI (Serial Peripheral Interface) interface protocol. It applies to the two-way information exchange between the controller (master) and the sensor/actuator (slave), to build the underlying network monitoring system. The bus takes the advantage of the electrical characteristics of CAN transmission line, and the bus inherits its anti-interference ability and the advantage of long transmission distance. Also, it inherits the merits of SPI bus communication such as fast, easy to use and low cost. Compared with the half duplex distributed network constructed by EIA-485, the slave in this bus is a pure hardware device, saving the MCU chip and software programming. This paper presents a new bus communication protocols and hardware structure of slave interface module and describes the working principle of the interface circuit. Finally, experimental data and test results are given, verifying the feasibility and communication features of this type of bus and the interface module design. [ABSTRACT FROM AUTHOR]